drm/amd/display: wait for the whole frame after global unlock

[why]
The current code will not wait for the entire frame
 after global unlock.
This causes dsc dynamic target bpp update corruption when
there is a surface update immediately happens after this.

[how]
Wait for the entire whole frame after unlock before continuing
the rest of stream and surface update.
Signed-off-by: Wenjing Liu <Wenjing.Liu@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c

@@ -1281,6 +1281,8 @@ void dcn20_pipe_control_lock_global(
 				CRTC_STATE_VACTIVE);
 		pipe->stream_res.tg->funcs->wait_for_state(pipe->stream_res.tg,
 				CRTC_STATE_VBLANK);
+		pipe->stream_res.tg->funcs->wait_for_state(pipe->stream_res.tg,
+				CRTC_STATE_VACTIVE);
 		pipe->stream_res.tg->funcs->lock_doublebuffer_disable(
 				pipe->stream_res.tg);
 	}